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![Lets Talk about systemd
Name: Praveen Kumar
Contact: kumarpraveen [AT] fedoraproject DOT org
Date: 2015-07-11
1](https://image.slidesharecdn.com/centosmeetup-150709092151-lva1-app6892/75/Basic-of-Systemd-1-2048.jpg)
![Service file Template
[Unit]
Description=The Apache HTTP Server
After=network.target remote-fs.target nss-lookup.target
[Service]
Type=notify
Environment=LANG=C
ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND
ExecReload=/usr/sbin/httpd $OPTIONS -k graceful
Service file Template
9](https://image.slidesharecdn.com/centosmeetup-150709092151-lva1-app6892/75/Basic-of-Systemd-8-2048.jpg)
![# Send SIGWINCH for graceful stop
KillSignal=SIGWINCH
KillMode=mixed
PrivateTmp=true
[Install]
WantedBy=multi-user.target
Service file Template
10](https://image.slidesharecdn.com/centosmeetup-150709092151-lva1-app6892/75/Basic-of-Systemd-9-2048.jpg)
Uploaded byPraveen Kumar
Basic of Systemd
Systemd is a system and service manager that provides modular, asynchronous, and concurrent services. It allows administrators to create snapshots of unit configurations. Some key capabilities it provides include listing and controlling systemd units and services. A service file template is also provided that defines properties like the service description, execution commands, and installation targets. Systemd-nspawn can be used to create lightweight containers with their own isolated namespaces.
Basic of Systemd
- 1. Lets Talk aboutsystemd Name: Praveen Kumar Contact: kumarpraveen [AT] fedoraproject DOT org Date: 2015-07-11 1
- 2. Agenda • What issystemd • What capabilities it provides • How to use systemd • How a service file looks like • Intro about systemd-nspawn • Resources Agenda 2
- 3. What is systemd •Modular • Asynchronous and concurrent • Create snapshot • features a fully language-agnostic API ... Much more What is systemd 3
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- 5. How to usesystemd • Default init system for CentOS • List out units • systemctl list-units • List out services • systemctl list-units --type service • systemctl list-units --type service --all How to use systemd 5
- 6. • systemctl list-unit-files--type=service • ls /usr/lib/systemd/system/*.wants How to use systemd 6
- 7. How to usesystemd cont... • List out targets • systemctl list-units --type targets • Check CGroup tree • systemd-cgls How to use systemd cont... 7
- 8. Service file Template [Unit] Description=TheApache HTTP Server After=network.target remote-fs.target nss-lookup.target [Service] Type=notify Environment=LANG=C ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND ExecReload=/usr/sbin/httpd $OPTIONS -k graceful Service file Template 9
- 9. # Send SIGWINCHfor graceful stop KillSignal=SIGWINCH KillMode=mixed PrivateTmp=true [Install] WantedBy=multi-user.target Service file Template 10
- 10. systemd snapshot • Cratea snapshot of existing unit config $ sudo systemctl snapshot test $ sudo systemctl -all list-units | grep test $ sudo systemctl show test $ sudo systemctl isolate test.snapshot $ sudo systemctl delete test systemd snapshot 11
- 11. sysemd-nspawn • systemd-nspawn isa small utility which is use to create light weight containers • Setup a container $ sudo yum -y --nogpg --releasever=7 --installroot=/srv/mycontaine install systemd passwd yum vim-minimal sysemd-nspawn 12
- 12. sysemd-nspawn cont... • Setupcontainer password $ sudo systemd-nspawn -D /srv/mycontainer • Start a container $ sudo systemd-nspawn -jbD /srv/mycontainer sysemd-nspawn cont... 13
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